Perioperative allergic reactions: experience in a Flemish referral centre.

Background The incidence of perioperative anaphylactic reactions is overall estimated to be 1 per 10,000–20,000 anaesthetic procedures. We performed a retrospective analysis of patients referred to a University Allergy Centre in Belgium with the suspicion of an allergic reaction during or shortly after general anaesthesia. Objectives Our aim was to assess the causes of perioperative allergic reactions, to evaluate cross-reactivity among neuromuscular blocking agents (NMBA) and to analyze the diagnostic relevance of tryptase levels in the discrimination between IgE and non-IgE-mediated reactions. Methods A total of 119 patients, referred from 2007 to 2011 were included. The diagnostic protocol consisted in case history, serum tryptase measurements, immunoassays and skin tests. Results A diagnosis of IgE-mediated reaction was established in 76 cases (63.9%). The most common agents were NMBA (61.8%), antibiotics (14.5%), latex (9.2%) and chlorhexidine (5.2%). Rocuronium was the most frequently causative NMBA (48.9%). Vecuronium cross-reactivity was established by skin testing in 47.6% of cases. Cisatracurium was the NMBA most frequently tolerated (cross-reaction in 13.9%). In 23.4% of NMBA allergic patients, the reaction occurred on the first exposure. Most IgE-mediated reactions occurred during the induction phase (72.4%). Latex-induced reactions occurred mainly during maintenance and recovery phases (71.4%; p < 0.02). Mean tryptase values were significantly higher in patients with IgE-mediated reactions (p = 0.0001), than in those with no identified cause. Conclusions NMBA, antibiotics, latex and chlorhexidine were the main culprits of IgE-mediated perioperative reactions. Uncertainties remain concerning the specificity and sensitivity of skin testing. Tryptase assays can be useful in the discrimination of IgE and non-IgE-mediated reactions.